Method of catalytic desulfurization of gases



March 3, 1953 E. B. MILLER 2,630,375

METHOD OF CATALYTIC DESULFURIZATION OF GASES Filed MarOh l2, 1951 10Sheets-Sheet 1 FIG.

1N VENTOR ERNEST B. MILLER @u fw ATTORNEYS March 3, 1953 E.. B. MILLER2,630,375

METHOD 0F CATALYTIC DESULFURIZATION 0F GASES Filed March 12, 1951A 1osheets-sheet 2 INVENTOR" n musn ATTORNY:

March 3, 1953 E. B. MILLER 2,630,375

METHOD OF' CATALYTIC DESULFURIZATION OF' GASES Filed March l2, 1951 10Sheets-Sheet 5 FIG. a. i

, 7? l /00 73 w /71 //7\ /l7 V l /50 i ./,Zfl I /J/ E l Y F I G 'a 4 n yf J w la V I INVENTGR f-L* enuesrammn BY fw ATTORNEYS March 3, 1953 E.B. MILLER 2,630,375l

METHOD OF' CATALYTIC DESULFURIZATION OF GASES Filed March 12, 1951 10Sheets-Sheet 4 NVENTOR 1 ERNEST B. MILLER BY M71@ ATTORNEYS March 3,1953 E. B. MILLER 2,630,375

METHOD OF CATALYTIC DESULFURIZATION OF GASES Filed March l2. 1951 lOSheets-Sheet 5 INVENTOR ERNEST B. MILLER BY VLM ATTORNEYS March 3, 1953E. B. MILLER 2,530,375

METHOD OF CATALYTIC DESULFURIZATION OF GASES F11ed March 12, 1951 1osheets-sheet e /7/// 77 a I /65 if 6'/ .l/ o )'70 INVENTOR' ERNESTB.MILLER Armlehnen?V March 3, 1953 E. Es.l MILLER l 2,630,375

METHOD OF CTALYTIC DESULFURIZATION OF GASES Filed March l2, 1951 lOSheets-Sheet 7 ATTORNEYS March 3, 1953 E. B. MILLER 2,630,375

METHOD OF' CATALYTIC DESULFURLZATION OF GASES Filed March l2, 1951 10Sheets-Sheet 8 INVENTOR ERNEST B. MILLER BY v/hq,

ATTORNEYS March 3, 1953 E. B. MILLER 2,630,375

METHOD 0F CATALYTIC DESULFURIZATION OF GASES Filed March l2, 1951 10Sheets-Sheet 9 FIG. I4.

FIG. l5

1N VENTOR ERNEST B. MILLER I BY ATTORNEYS March 3, 1953 E. B. MILLER2,630,375

METHOD OF' CATALYTIC DESULFURIZATION OF GASES Filed March 12, 1951- 10Sheets-Sheet lO W n 0 N M e Q Q \J INVENTOR- ATTORNEYS Patented Mar. 3,1953 METHOD oF CATALYTIC DE sULFURIzATIoN oF GASES Ernest `B. MillenHouston, Tex., assignor to Jefferson Lake Sulphur Company, New Orleans,La., a corporation of New Jersey Application March 12., 1951, Serial No.215,181

This invention relates to the `recovery of sulphur from gases containingsulphur compounds and has more particular reference to a novel method ofrecovering elemental sulphur in liquid form from gases containinghydrogen sulphide.

The object of the present invention is to provide a novel method ofrecovering elemental sulphur from gas containing hydrogen sulphide bycatalytically desulphurizing the gas to obtain liquid sulphur.

vAnother object of the invention is to provide a novel method ofrecovering elemental `sulphur from gases containing HZS in which acatalyst is used which is ableto effect a highly efficient conversion ofHzS to H2O and sulphur'and in which the catalyst, after it has becomespent, due to chemical reduction of the catalytic agent or thedeposition of carbon `or other contaminants from the gas being treated,may be fully restored to its initial efficiency byreactivation with hotair. y

Another object of the invention is to provide a novel method ofrecovering elemental sulphur from gases containing HzS, as characterizedabove, wherein the gas to be treated is brought into contact with thecatalyst in `at least two successive reaction zones, in which sulphurvapor is formed, prior to its passage to a scrubbing or condensing zonein which the sulphur vapor is condensed to form liquid sulphur,

Another object of the invention is to provide a novel method ofrecovering elemental 'sulphur' from gases containing HzS, ascharacterized above, wherein a portion of the liquid sulphur beingrecovered is returned to a sulphur burner, where it `is burned to supplythe oxidant required to oxidize the HzS in the gas being processed.

A further object of the invention is to provide a novel method ofrecovering elemental sulphur from bases containing I-IzS, ascharacterized above, wherein the temperature rise in each reaction `zoneis controlled by controlling the supply of oxidation gas to such zones.

Other objects and advantages of the invention will appear in thespecification when considered in connection with the accompanyingdrawings, wherein:

Fig. 1 is a plan view, with parts omitted, showing one form of apparatusand the arrangement thereof for carrying out the method of the presentinvention;

Fig. 2 is a side elevational view of the apparatus shown in Fig. l, andshowing the second converter and its appurtenances and the secondscrubbing tower and its appurtenances;

Fig. 3 is a side elevational view of the nrstV converter and itsappurtenances, shown in Fig. 1;

Fig. 4` is a side elevational View of the `rs't scrubbing tower and itsappurtenances, shown in Fig. 1;

Fig. 5 is a plan view of a converter;

Fig. 6 is a side elevation, partly in section, of

the converter driving mechanism;

Fig. 'I is a vertical sectional view of the converter, taken on the line'l--l of Fig.` 5,' but omitting the driving mechanism;

Fig. 8 is a horizontal sectional view of the con# verter, taken on theline 8- 8 o f Fig. *7, butdrawn to a smaller scale;

Fig. 9 is an enlarged vertical sectional view of" the seal shown in theright hand side of the upper manifold of Fig. 7;

Fig. 10 is a plan view 'of the seal shown in Fig. 9;

Fig. 11 is a vertical sectional'view taken on the 14, 'and Fig. 16 is adiagrammatic view showing the ilow of the gas to be desulphurized; thelow of the oxidation gas; andthe now of the 'regenerating medium'through the system.

In general, the invention comprises a method i ofcatalytic'desulphurization of gases containing hydrogen sulphideyand'therecovery `of elemental sulphur therefrom in liquid form.

For the purpose -of illustration, the rinventio will be describedin-connection with the catalytic desulphurization of sour natural gasand the. recovering of elemental sulphur therefrom in liquid form.

Referring now to the drawings, there is shown,

in Figs. l to 4 inclusive, one embodiment ofap paratus and thevarrangement thereof for carry ing out the method of this invention. Theap.- parat-us shown includes a iirst three-stage 4rotary catalytic`converter or reactor 5, two stages of which are used `as reactionchambers or zones, in which the sour gas is brought into intimatecontact with the catalyst, and the other stage is used as an activationchamber or zone in which` the lcatalyst is regenerated.; .a rstpre-heater 6 for heating the sour gas prior to its passage through the`iirstreaction stage of the converter` a heat exchanger 1 for heating orcooling the sour gas between the first and second reaction stages of theconverter 5; a first scrubbing tower 8 for separating the liquid sulphurfrom the treated gas; a second three-stage rotary catalytic converter 9,two stages of which are used as reaction chambers or zones in which thesour gas is brought into intimate contact with the catalyst and theother stage is used as an activation chamber or zone in which thecatalyst is regenerated; a second pre-heater Ill for heating the sourgas after its passage through the first scrubbing tower and prior to itspassage through the rst reaction stage of the second converter 9; asecond heat exchanger II for heating or cooling the sour gas between therst and second reaction stages of the second converter 9; a secondscrubbing tower I2 for separating the liquid sulphur from the gaseousadmixture after its passage through the second converter; a heater I3for heating the regenerating medium. preferably air; a fan or blower I4for supplying air under pressure to the heater I3: a sulphur burner I5,in which a miYture of liouid sulphur and air is burned to produce a gasof combustion having as bigh an SO2 content as nossiblepreferablylll-20%: and a waste heat boiler le which utilizes tbe heat of the gasesof combustion in the sulphur burner to generate `steam for runningauvlliarv machinery and otber purposes. 'The sulphur burner l 5 and thewaste beat boiler IE :may be of anv suitable. usual tune. '.Tbe burnerI5 is sbovfn as having a liouid snlnlour sunnlv pine I1 connected tosunnlv liouid `sulnbur from the scrubbing towers. and an air surplv pineIR connected to bot air blower I4 for sunnlving air under pressure tothe burner.

The two Converters or reactors 5 and 9 are preferably .supported in anupright raised position bv .suitable framework, indicated generally at ll and 20. respectively.

The rntgrv nnnverters E and 9 are identical in crmetmmtinn and are.cene-rauw similar tn the man.. verter shown, in uw nnngndingavnliparinn, ,cmg Nn. '779 R24- 51er] flntnloer 14 104'7` forllfl'etlanfi nf and. vArmar-atm@ for l'ieeulnburi'zatien of Gases, nowTT. S, Tetters Patent No, 9.561900 issued .Tulv 24. 1951. 'Tbe details mthe converter are shown in Wigs, 5 to l5. inclusive. As there sbown.each nf tbe Converters comprises a pressure. vessel 2l. unner and lowermanifolds 2" 9* m'l" mounted within tbe vessel? a corn'oartmpmivpdannular drum 9d rotatably mmmted within the pressure Veqgpl between 97ndin cnmi'vlllrlirlllnn with the manifolds* and .suitable drivingmechanisrn for rotating the annular drum.

The pressure vessel 2l is hreterabl fnImPl lll WG Darts. an imber-Flervferl .slaell nr aan 25 and a, lower flanged .shell 2R suitablyioinerl togetber. as lav boltine' to form a eas-ti'rbt ioirit.

The annular drum 24 is xedlv attached as bv means of plates 21. 2R. to acentral vertical shaft 29 suitably iournaled in bearings carried bv theupper and lower shell members 25. 2G.

The mechanism for rotating the annular drum is supported on a platform30 mounted on the upper shell 25 and includes a shaft 3i connected tothe upper end of the shaft 29 by a coupling 32 (see Fig. 6). The shaft3I is driven by suitable reduction gearing mounted in a housing 33, thereduction gearing being belt-driven by a motor 34 (see Fig. 5).

The rotatable annular drum 24 comprises two spaced concentric cylinders35, 35, which form the side walls; two spaced annulai` plates 31, 38,

each secured to the top of the cylinders 35, 36, respectively, form thetop of the drum, the space between the annular plates 31, 38 forming anannular opening 39 in the top of the drum; two

spaced concentric annular plates 40, 4I, each secured to the bottom ofthe cylinders 35, 36, respectively, form the bottom of the drum, thespace between the annular plates 40, 4I forming an annular opening 42 inthe bottom of the drum (see Fig. 7).

The rotatable annular drum is divided into a plurality of compartments43 by radial partitions or dlaphragms 44 (see Fig. 8). In each of theradial compartments 43, near the bottom thereof, there is provided aplate 45 attached to the walls of the compartment, as by welding, toform a gas-tight joint (see Fig. 7). Each plate 45 forms a support forone or more tubular catalyst containers 46. In the particular embodimentshown, only one such container is shown mounted in each compartment.

The catalyst containers 46 are identical in construction and, as shownin Figs. 14 and 15,

each comprises two concentric tubular wire screens 41, 48 held in spacedrelation by a plurality of longitudinal radial ns 49. with the annularspace between the screens closed at the bottom. The mesh of the screenis such as to retain a granular catalyst material 50 in the annularspace between tbe screens. Although the invention is not limitedthereto. it is preferred to employ a. catalyst wherein granular silicagel or a substance having substantially the .same structure is thecarrier for the active material. OX- ide of copper. nicl-fel, andmanganese may be employed as the active material. However. iron oxide ispreferred. In connection with the foregoing, `it may be pointed out thatthe annular beds of catalyst material are so tbin that they permitvelocities of about from l0 to 25 feet per minute through the beds at60-70 F. and atmospheric pressure.

Each ot the containers Mi is closed at its, top by means of concentricboobs 5I. 52 mounted on the concentric screens 41. 48 and a cover plate53 detachablv connected to the inner hoop 52. as by screw bolts. andhaving a depending annular trough-shaped flange 54 viitting between thehoops 5|. 52, A depending annular iin 55 is secured to the flange 5!!and proiects downwardly between and below the hoops 5I, 52. and fits inslots 5S formed in the upper ends of tbe radial iins 48, all as shown inFig. l5. The construction is such that. as tbe catalyst settles down.leaving a space between the top portion of the wire screens devoid ofcatalysts. the iin 55 will prevent gas from passing through the spacedevoid of catalyst. Each container 46 is detachably mounted on a nozzle51 proiecting upwardly from an onening 58 formed in the plate 45. asclearly shown in Fig. '1. The nozzle 51 is secured in the opening 58. asby welding, to form a gas-tight joint.

The top and bottom manifolds 22, 23 are mounted on the top and bottom ofthe annular drum 24, in communication with the annular openings 39, 42formed in the top and bottom ofthe drum. The manifolds are identical inconstruction and each is formed in the shape of an annular trough havingan annular top (or bottom) 59 and annular side walls 5l), 6I (see Fig.9).

A. plurality of compression springs 62, mounted on brackets 63 suitablysecured to the inner walls of the vessel 2l, yieldably press the top andbottom manifolds against the top and bottom, respectively, of theannular drumA (see Fig. 7). The

top and bottom-manifolds are-held stationaryrele. ative-tokthe-rotationy ofv the drum bymeans` hereinafter to--be described, and,to prevent the-.ese cape of f gas between; the rotatingl drum and, themanifolds, sealing ring gaskets-f Stare placedat the-junction of theside-walls of` the manifolds and the drum. The sealing ring gaskets 64?are held in tight sealing engagementwiththe top andibottom ofthe-drum bymeansof annular hoops 65 which encircle the gaskets and hold themagainstthe sidelwallsof the manifold. The upper (or lower) ends ofthehcops' aresecuredtothe top (or bottomi plate of` themanifold; as bywelding. The ring gaskets are retained. between thehoops.l t5' and theside walls` E0, 6;! of the manifolds byvmeans: of a. plurality ofcircumferu entially spaced. threadedf bolts 66; which engage` the ringgaskets and the lower portions` of the hoops and side walls. Thel ringgaskets Mare yieldably` held in. engagement with the i top and bottom ofthedrum 24 by means of a. plurality of4 compression springs ti: mountedon stud bolts 68 secured to the 'top (or bottom) of the` manifolds. andengaging4 annular plates or members- 69 mounted on the topior bottom) ofthe. ring gaskets, all as clearly shown in Fig. 9.

At three circumferentially spaced points in the top and bottommanifoldsgthere arelocatedseals which, by reason of the sliding contactofthe radial partitions Ml against the under surface. of the bottoms oftheseals, divide the` manifolds and drum into three. sectors, eachsector gas-tight withrespectto. the adjacent; sectors.. The seals. areidentical in construction and the details thereof; are best shown. inFigs; 9, l0 and 1li. Each seal includes a bottom or `sealing plate itmounted within the manifold between spacedy radial partition walls "Hl,72. 1i) is yieldably urged against` the top` (or bottom) of the drum andrests on the concentric plates 31, 38 which form the top of the drum (orplates 4U, 4l which form the bottom of the drum), as shown in Fig; 9.The side edges of the plate 1i! are bifurcated, as shown at 13, 14, forthe recep tion of gasket strips 15, 16, which are yieldably pressedoutwardly against the partition walls ll,

I2 of the`- seal by leaf springs Tl, '18,t as shown in.

Figs. 1G and l1.

The means for yieldably pressing the bot-- tom plate 'l0 of the sealbetween the top (or bottom) of the drum comprise a plurality ofcompression springs i9. mounted. on` projectionsY 80, formed on` theupper surface of the plate 10, The springs '19.u engage the top (or.bottom) of the seal and are held in position by bolts SI projectingthrough the top (or. bottom) of the seal andv coiled springs andthreaded into the projections formed on the plate 10.

Each radial partition or diaphragm 4M has a.

portion of its top. and. bottom edges extending upwardly (ordownwardly), between the edges of the openings in the top and bottom ofthe drum. A, gasket 82' is secured on these portions and exetends above(or below.)` their top (or bottom) edges and engages the under face ofthe bottom plate'lofthe sealA (seeFg, 11)

Plates 83 areA secured to the tops and bottoms of the partitions andareheld spaced therefrom;

by a spacer strip 84, the plates and spacer strip being secured to thepartitions by'bolts 85; gaskets 82 are. confined between the partitionsand the plates 83, as by means of bolts 86, and are pressed upwardly (ordownwardly').Y against the under surface of the bottom plates 1i) of theseals by means of leaf springs' Sli, all as shown in Fig. 11.

The bottom plate Iniiordery; to prevent: the gaskets :82.- from.:`beingJ unduly pressedupwardly:` (orf downwardly) when the1 gaskets: arenot"` engaging thebottoms off the seals,v means'l areprovided forspanning the reaches` of themanifolds between the seals:v TheseA means`comprise spaced.'V pairs oftu curvedf` plates 88, 89 which extendbetween andare secured tothe partition walls of the seal, as shown inEig. 12. 83., were. in the same horizontal plane. asithe bottom surfacesof the bottom plates 105.01 the` seals, so` that. as the gaskets 82.moveoutoffengagement withthe; bottom plate of the seal, they immediatelyengage the plateslg `89..

A. plurality of rollers 9m areV mountedN within the topand bottommanifolds. These rollers are circumferentially spacedf within themanifolds and.` are; adapted to; engagepthe` annular.` plates- 31.,V43;. whichform parts of. the. topand bottom. respectively, oftherotatable drum;` ThesearollersA are adapted. to prevent frictionalsurface engage:-

ment: between thesi'de walls of4 the. manifolds and4 the. top andbottomof; the. drum.. Thesarollersz, are;` identical. inV constructionand f mounting and; each: comprises: a threaded stud bolt: Sl screwed.into the: outer side: Wall 60 oflxthei manifold; a. balli race;` 9-1Jfixedly` mounted. on. thewbolt. and a. wheel 93: mounted. on theA ball`race; allas shown'r iniFig. 13a

Three hanged pipes or conduits `Sill, 95.,` 96 hav.` ing threaded ends,project through the cap of the vessel 2! and have4 their threaded endssecured to. the top. plate of. the top.. manifoldby means. of lock.nuts. 9.1. whichA form. gasftightt secured to` the bottom. plate. of thebottom mani foldby means of locknuts 9T Whichform gas.- tight joints.`Thesel pipes are,` welded to thebotf.- tomof the vessel. 2l.. and. holdlthe bottom manifold stationary relative to the rotation` of the'.

drum.` yEhese pipes are circumferentiallyspaced with respect. tothebottom manifold and each. is secured to and communicates withthe-manif: fold: at a; point located between the seals. The width oftheseals withrespecttotheradial com-` partments.; 43 containing thecatalyzing units is.

such.. that. at all times at least. one of the par. titions` ordiaphragms 44; is engaging the bottom plate 'l0-1 of the seal ingas-tight engagement;

From the foregoing, it will readily: be-seenthat by theengagementrof theradial partitions: with thel seals, the manifolds and drum areV dividedinto three gas-tight` chambers orV sectors, called, for convenience, thefirst' reaction` stage, the second reaction stage; andi the activationstage.

The drum carryingi theV tubular catalyst con. tainersisrotatedcounter-clockwise; as' viewed in Fig. 5', and, as'it rotates; thetubular catalyst containers are successively moved through thethreelstagesin the following order: the second reaction' stage,V thefirstv reactionstage, and the activation stage.

The now of the gas to be treated, the flow of the oxidant gas, and thenow of the regeneration medium are. showrrschematically in Eig. 16a

The sour4 gas toibo tneatecll delivered; underl The bottom surfaces of.the1 plates suitable pressure from a source of supply (not shown), tothe lrst pre-heater 6, by means of a pipe line I I. The gas is heated inthe pre-heater to an optimum pre-reaction temperature and then passesthrough a pipe line |92 to the first converter and enters the topmanifold of the first reaction stage through pipe 94.

The oxidant gas, preferably SO2, for the first reaction stage of theconverter 5, is delivered under suitable pressure, from the sulphurburner I5 through a supply pipe line |93 and a branch valved pipe linelill! connected to the pipe line |02. The mixture of sour gas and SO2passes downwardly from the upper manifold through the opening in the topof the drum into the various compartments of the drum containing thetubular catalyst containers, as are at that time contained within thesector forming the first reaction stage. The gaseous mixture passesthrough the pervious layer of catalyst material into the hollowinteriors of the tubular containers; thence, downwardly through theopening in the plate 45 into the bottom of the drum, and through theopening therein into the bottom manifold. When the mixture of sour gasand SO2' comes into intimate contact with the catalyst an exothermicreaction takes place in which elemental sulphur is liberated in vaporform, together with steam. in accordance with the following equation:

From the bottom manifold, the treated gaseous admixture passes throughpipe 98 and pipe line |05 into the first heat exchanger l, where itstemperature, which has risen in the reactor, is adjusted to an optimumpre-reaction temperature. From the rst heat exchanger the gaseousadmixture passes through pipe lines |06 and 95 into the top manifold ofthe second reaction stage of the converter 5.

The oxidant gas, preferably SO2, for the second reaction stage of theconverter 5. is delivered under suitable pressure through a branchvalved pipe line |91 connecting the supply line |03 and. the pipe line|96. The gaseous admixture moves downwardly through the second reactionstage of the converter 5, in a manner similar to its downward movementthrough the rst reaction stage and during its passage further reactiontakes place, liberating more elemental sulphur vapor and steam.

From the second reaction stage of the first converter 5, the treatedgaseous admixture passes through pipe 99 and pipe line |98 into thebottom of the first scrubbing tower 8. The treated gas mixture includingthe sulphur vapor and steam formed by the reactions in the converter,rise inthe scrubbing tower against a downward flow of molten sulphur,which condenses the sulphur vapor into molten sulphur, which collects inthe bottom of the tower.

From the top of the rst scrubbing tower 8, the partially desulphurizedgas passes through pipe line |99 into the second pre-heater Ill, whereits temperature is adjusted to an optimum prereaction temperature. Fromthe second preheater, the gas passes through pipe line I l!) and pipe 94of the second converter 9 into the top manifold of the rst reactionstage of the second converter 9.

1 The oxidant gas, preferably SO2, for the rst reaction stage of theconverter 9 is delivered under suitable pressure through a branch valvedpipe line |I|. connecting the supply line |03 and 8 the pipe line I I0.The gaseous admixture moves downwardly 'through the rst reaction stageof the second converter in a manner similar to its downward movementthrough the first reaction stage of the rst converter and during itspassage further reaction takes place, liberating more elemental sulphurvapor and steam.

From the rst reaction stage of the second converter the treated gaseousadmixture passes through pipe 98 and pipe line II2 into the second heatexchanger where its temperature, which has risen in the reactor, isadjusted to an optimum pre-reaction temperature. y

From the second heat exchanger I the treated gaseous admixture passagesthrough pipe line II3 and pipe 95 of the second converter 9 into the topmanifold of the second reaction stage of the second converter 9.

The oxidant gas, preferably SO2, for the second reaction stage of thesecond converter is delivered, under suitable pressure, through a branchvalved pipe line ||4 connecting the supply pipe line |93 and the pipeline M3. The gaseous admixture moves downwardly through the secondreaction stage of the second converter in a manner similar to itsdownward movement through the first reaction stage of the rst converterand during its passage further reaction takes place and the remainingelemental sulphur is liberated in vapor form.

From the second reaction stage of the second converter, the treatedgaseous admixture passes through pipe 99 of the second converter 9 andpipe line I I5 into the bottom of the second scrubbing tower I2. Thetreated gaseous admixture, together with the steam and sulphur vaporformed by the reactions in the second converter, rises in the secondscrubbing tower against a downward flow of molten sulphur, whichcondenses the sulphur vapor into molten sulphur which collects in thebottom of the scrubbing tower. From the top of the second scrubbingtower, the now sweet gas passes through a pipe line IIS to its point ofuse (not shown).

As schematically shown in Fig. 16, air for use as the regeneratingmedium is forced into the hot air heater I3 by means of the fan orblower I4. The air is heated to a temperature of about 1000 F. in theheater and, from the heater, passes through supply pipe line and branchpipe line IIS to the rst converter 5 and enters the bottom manifold ofthe activation stage through pipe |90. From the bottom manifold, the hotair passes through the opening in the bottom of the drum into thebottoms of the various compartments of the drum as are at that timecontained within the reactor forming the reactivation stage; thence,upwardly through the openings in the plates 5, and up into the hollowinteriors of the tubular catalyst containers, through the perviouslayers of catalyst material into the compartments of the drum; thence,upwardly through the opening in the top of the drum into the topmanifold. As the hot air passes through the catalyst material, anyimpurities in the form of tars or carbonaceous matter are burned 01T andthe catalyst material is reactivated. From the top manifold of theactivation stage, the hot air is exhausted to the atmosphere throughpipe 96.

I-Iot air for use as the regenerating medium for the reactivation stageof the second converter passes from the air supply pipe IIl and branchpipe line |I9 to the second converter and enters the bottom manifold ofthe reactivation stage -paratus of -xed size.

:through-pipe 1100 fof fthe `second `converter. u".E'he

hot air :passes "upward through the reactivation stage of the secondconverter in a mannerfsimilar to its upward passage through thereactivation stage lof 4the grst fconverter sand, during its pasusage,:regenerates `the catalyst material therein.

While the -foregoing description of'thcmet'hod khas not been :concernedwith `the utilization rof lance for the differential pressure, areasonable increasein the over-all-operatingpressures will permit`handling larger gas `volumes in anap- The particular apparatus shownis` designed to. handle gases at #high preszsures; although it iscontemplated that the :meth- -od hereindescribed can be `practiced by.utilizing pressures of from :about 5 lbs. to `10.lbs. per square inch.

The presentmethod is contrived to.recover a major portion of the`contained sulphur in the `sourgas in aimultifstage oxidation processwithout raising the reaction temperature .in any stage kaboveaboutSO" F.by adjustingfthe temperature of the ladmixture of thegas to be treatedand the sulphur liberating gas, .illustratively SO2, to anAoptimum.pre-.reaction temperaturein the range of fromabout 375 F. `to`about 600 F. prior to tions of the contained sulphur may be removed inthe respective stages when employing pre- .reaction .temperatures uptoabout 800 while controlling the reaction 'temperatures in the stages sothat they do not exceed about 1000" F. in any stage. It will'beunderstoody however, that atv higher reaction temperatures than above'830 F., the eili'ciency of the conversion will be reduced. Therefore,-it is highly `preferable Ato vpractice the method at relatively lowreaction temperatures.

As a specific example, assume that the .raw gas to betreated contains125 lbs. of `HzS per 4300 cubic feet .at a pressure of .10V lbs. gaugeand at 100" F. Then, about 30% of the initial H2S ,content of the `gascan be converted .into sulphur `vapor in therlrst oxidationstage of the"rst group of reactors by pre-heating the Ygas to about 500 F. andmixing SO2 with the preheated gas at the rate of about 30,1bs. Yof `SO2per minute prior to the entry of the gas into the reactor in which therst oxidation stage occurs. The temperature in the reactor wllrise tofrom about 720 F. to about 750 F.

About of the initial HzS content of the `gas Ican be converted intosulphur `vaporin the second oxidation stage of the rst group of re-.actors by cooling the` gaseous admixturc delivered from the iirstoxidation stage to about 500 F., then mixing SO2 with the cooled gaseousmixture at the rate of about 30 lbs. ofSOz per minute prior to its entryinto the reactor in which the second oxidation stage occurs. Thetemperature in the reactor will rise to from about-680 F. to about '710`F.

About 30% of the initial total I-IzS content of the gas can be convertedinto sulphurvapor in the first oxidation stageof thesecondgroup ofreactors by pre-heating thegas after-its pas usage `through the .rstscrubbing-tower :to about :500 iF. :and Lmixing .SO2 `with thepre-.heated gas .at the rate rofl-about 430 A.-lbs. of SO2 per .-minute.prior ito :its entry into :the reactor in `the 4secondigroup :of`reactors `in which -the *rst 5 oxidation :stage occurs. Thetemperature'in the :reactoriwilllrise to from -iaboutf670 F. :to .about 700 F. Theremaining 1.0% Aof the initial total A'I-IzS content of the gas :can Abe`converted into sulphur vapor Yin 'the second oxidation stage l:of

41() the Asecond group .of reactors :by cooling .the

gaseous fadmixture ldelivered from the rst oxidation-stage to aboutr50.0 F., .thenmixing .SO2 lwith fthe fcooled gaseous Aadmixture -at therate of about `1.1 ,lbsnof `SO2 per minute prior to :its entry into fthereactor of the second group fof .reactors in which .thesecond,oxidationfstage occurs. The temperature .inl `the reactor will rise tofrom about 530 F. toabout ,560

Obviously, with a `raw ,gas vhaving sa imuch 420 lesseixHpgS content, itwillbepossible .to remove @all of the H28 in V.the first group ofreactors :zwithout raising lthe .temperature in .either :the

lrst vor :second .oxidation stages above a `permissble reactiontemperature of l,from about .25 747 F. to about 830 F.

It is `always advisable,r however, ito do `fas-much :oxidation .as'possible in `the first :.stage, consistent .with the above'fmentionedreaction item- ;peratures, so that :it has been found` advisable, fwhen.treating a :.gas :containing Yabout 315% .HzS, `to vsupply oxidantgases :to :the `various .stages so as to accomplish zabout 955% :conver-:sionn the rstlstagarabout .25% .inthe second stage, :about 412% .in thethird fstage, and8% in `.the last stage. Since, Ainthevearler stages,.the catalytic conversion can not be "completed, :the reaction `inthesestages-.can be assisted .by `.thepresence of an .excess of ioxi'dantgas.Thus, ..to .accomplish `the .illustrative :reactions above, `it thasbeen found .convenient `to supply :about '7.5% fof thefltotaloxidanttgasin `therirst stage and 'the :remaining ^"25% `in the :secondastage. Thexexcess notzused'upmreither of these .stages is .carried"with "the gas :to be treated, `andiis y `available as needed-lin thelastctwowstages.

In connection with the foregoing, aitimaysbe lpointed outfthat, "as the.boiling ,point of .sulphur -1is 1832 F a `pure sulphur vaporwouldcondense Ito liquid Aif cooled .below fthatltemperature. `;In

`the present method, fas :abovedescribed, there 50. is inoconcentratedsulphur vat any point. In fact, -the maximum concentrationisabout 2%, at which concentration the -sulphur vapor Will -remain in`vapor form atfthepressures anditemper-atures employed `in thefprocess.

While .it :is :not a necessary feature fof the invention, it may bepointedout that, -if the liberated sulphur content .of `the treated 3gas `becomes too high between the rst andsecond oxidation stages of`either group of reactors, :all `,or part "of .itlma'y be removed. This`is Vreadily accomplished, fior example, by suitable adjust- .ment .oflthe .heat exchangers 7 `land .fl'|.

`The scrubbing i towers Vii .and `l2 may `be of any suitable `usualtype. In the :particular embodiment illustrated, molten `sulphur iswithrdrawn from thefbottomof the` scrubbing tower -8 through ipipe line`V20 bypump [2| ,and `deliveredtofa `sulphurcooler .|22 through apipe7oline 123. From the sulphur 'cooler 122, the molten sulphur passesthroughgpipe line |124 to thevtop `of the scrubbing tower 8. :The`molten `sulphur cascades downwardly through thescrubbing ,tower andiscbrought :into intimate lcontact with the counter-current r stream Aof.-gas, `:steam fr and elemental sulphur vapor rising through thescrubbing tower and condenses the sulphur vapor into vmolten sulphurwhich collects in the bottom of the tower. In like manner, moltensulphur is withdrawn from the bottom of the scrubbing tower |2 through apipe line |25 by a pump |26 and delivered to a sulphur cooler |21through a pipe line |28. From the sulphur cooler |21, the molten sulphurpasses through a pipe line |29 to the top of the scrubbing tower |22 andcascades downwardly through the tower in counter-current to the upwardflow of gas,

steamand sulphur vapor therein and condenses f the sulphur vapor, whichcollects in the bottom of the tower. A portion of the molten sulphurbeing recirculated through -the two scrubbing towers, is withdrawnthrough a, pipe line |30, which is connected to a cross pipe line |3|connecting the discharge pipe lines |24 and |28 from the sulphur coolers|22 and |21, and delivered in its molten state to a sulphur cooling andflaking machine (not shown). Pipe line l1, through which liquid sulphuris supplied to the sulphur burner I5, is shown as being connected topipe line |30.

By mounting the annular drum and the manifolds of the converter withinpressure vessels, the method may be carried out with highV pressuregases and, too, the equalization of pressure within the drums, manifoldsand vessels, permits the drums and manifolds to be made of lighterweight material, which adds considerably to the efcient and economicaloperation of the converters. This equalization is accomplished by meansof a small opening |32 formed in that portion of the pipe line 94 withinthe vessels 2|. It is also considered desirable to provide each of thesix pipes 94, 05, 96, 98, 99 and of each of the converters withexpansion joints |33, located a short distance from their points ofconnection to the manifolds. This may be necessary, due to the unequaltemperatures of the gases and media as they pass through the varioussectors, thereby resulting in unequal. expansion of the parts of thedrums and manifolds.

. While two three stage rotary converters have beenrshown, obviously,one converter may be used, if desired, in which case, the treated gas,

Y after passing through the first scrubbing tower y 8, would be sent toits further point of use by means of a valved by pass conduit |34connected to valved conduit |09.

From the foregoing, it readily will be seen that there has been provideda novel method of recovering elemental sulphur in liquid form from gasescontaining HzS, which provides for carrying out the reaction process inat least two oxidation stages with control of the temperature rise ineach stage, thereby permitting the reaction process to be effected attemperatures below about 800 F., with resulting increase in efficiencyof the process, use of less expensive apparatus, and permitting the useof a catalyst carrier such as silica gel.

While the invention has been described in connection with thedesulphurization of sour gas, obviously, it is also applicable to thedesulphurization of other types of sulphur-containing gases and vaporswhich are subject to the action of a suitable catalyst.

Obviously, the invention is not restricted to the particular embodimentthereof herein shown and described. Moreover, it is not indispensablethat all of the features of the invention be used l2 conjointly, sincethey may be employed advantageously in various combinations andsubcombinations.

What is claimed is:

l. In the recovery of elemental sulphur in liquid form from gasescontaining H2S involving the contact of a catalyst with the gascontaining HzS to form sulphur vapor and the subsequent treatment of thecatalyst in an oxidizing atmosphere to regenerate the catalyst forfurther contact with the gases containing HzS and the subsequentcondensation of the sulphur vapor to form liquid sulphur, theimprovement which comprises rotating a series of separated thin beds ofcatalyst directly and in succession and substantially continuouslyrelative to and through a series of reaction zones and a regeneratingzone; continuously directing the flow of the gas to be treated insuccession and in series through said reaction zones; subjecting the gasto be treated to heat exchange to bring its temperature to an optimumreaction temperature and mixing a predetermined amount of oxidant withit prior to its passage through each of the reaction zones to convert aportion of the H2S in each of said zones into sulphur vapor and steam;continuously withdrawing the treated gas from the last one of thereaction Vzones and directing its flow through a condensing zone andthere condensing the sulphur vapor to form liquid sulphur; andcontinuously directing the ow of a hot oxidizing medium through theregenerating zone to reactivate the catalyst therein.

2. The method, as set forth in claim l, wherein the direction of theseries flow of the treated gas is opposite to the direction of rotationof the catalyst beds, whereby the treated gas will alway-s make its lastpassage through freshly activated catalyst beds.

3. The method, as set forth in claim l, including rotating a secondseries of separated thin beds of catalyst directly and in succession andsubstantially continuously relative to and through a second series ofreaction zones and a regenerating zone; continuously withdrawing thetreated gas from said condensing zone and directing the flow of thewithdrawn gas in succession Vand in series through said secondsuccession of reaction zones; subjecting the withdrawn gas to heatexchange to bring its temperature to an optimum reaction temperature andmixing a predetermined amount of oxidant gas with it prior to itspassage through each of said second series of reaction zones to converta portion of the HzS in each of said second series of reaction zonesinto sulphur vapor and steam; continuously withdrawing the treated gasfrom the last one of the reaction zones of said second succession ofreaction zones and directing its flow through a second condensing zoneand there condensing the sulphur vapor to form liquid sulphur; andcontinuously directing the flow of a hot oxidizing medium through theregenerating zone of said second succession of zones to reactivate thecatalyst therein.

4. The method, as set forth in claim l, including the step of burning amixture of sulphur and air to make SO2 and supplying the SO2 for use asthe oxidant.

5. In the recovery of elemental sulphur in liquid form from gasescontaining I-IzS involving the contact of a catalyst with the gascontaining HzS to form sulphur Vapor, the subsequent treatment of thecatalyst in an oxidizing atmosphere to regenerate the catalyst forfurt-her contact with the gas containing I-IzS and thesubsequentcondensation of the sulphur vapor to form liquid sulphur, theimprovement which comprises rotating a series of beds of catalystdirectly and in succession and substantially continuously relative toand through a series of reaction Zones and aV regenerating zone;continuously directing the flow of the gas to be treated in successionand in series through said reaction zones; subjecting the gas -to betreated to heat exchange to bring its temperature to an optimum reactiontemperature and mixing With the gas to be treated an amount of SO2suilicient to convert a portion of the HzS into sulphur vapor and steam,Without raising the temperature of reaction in any of the zones aboveabout 800 F. prior to its passage through each of the reaction zones;continuously withdrawing the treated gas from the last one of saidreaction zones and directing its ow through a condensing zone and therecondensing the sulphur vapor to form liquid sulphur; and continuouslydirecting the flow of a hot oxidizing medium through the regeneratingzone to reactivate the catalyst therein.

6. The method, as set forth in claim 5, including rotating a secondseries of separated thin bed-s of catalyst directly and in successionand substantially continuously relative to and through a second seriesof reaction zones and a regenerating zone; continuously withdrawing thetreated gas from said condensing zone and directing the flow of thewithdrawn gas in succession and in series through said second successionof reaction zones; subjecting the gas to be treated to heat exchange tobring its temperature to an optimum reaction temperature and mixing withthe gas to be treated an amount of SO2 suilcient to convert a portion ofthe HzS into sulphur vapor and steam without raising the temperature ofreaction in any of the zones above 800 F. prior to its passage througheach of the reaction zones; continuously withdrawing the treated gasfrom the last one of the reaction zones of said second succession ofreaction zones and directing its flow through a second condensing zoneand there condensing the sulphur vapor to form liquid sulphur; andcontinuously directing the flow of a hot oxidizing medium through theregenerating zone of said second succession of Zones to reactivate thecatalyst therein.

7. The method, as set forth in claim 5, including the step ofwithdrawing a portion of the liquid sulphur from the condensing zone andburning it to supply the SO2.

tion zone and a regenerating zone; mixing a predetermined amount of thegas to be treated with a predetermined proportion of sulphur-liberatinggas and continuously directing a flow of the mixed gases at an optimumpre-reaction temperature through said reaction zone to convert the HzSin said reaction zone into sulphur vapor and steam; continuouslywithdrawing the treated gas mixture from said reaction zone anddirecting its ow through a condensing zone and there condensing thesulphur vapor to form liquid sulphur; and continuously directing theflow of a hot oxidizing medium through the regenerating zone toreactivate the catalyst therein.

9. The method, as set for-th in claim 8, including the step of burning amixture of sulphur and air to make SO2 and supplying the SO2 for use asthe oxidant.

10. The method as set forth in claim 9, in which the sulphur is obtainedby recycling a portion of the recovered liquid sulphur.

ERNEST B. MILLER.

REFERENCES CITED The following references are of record in the iile ofthis patent:

UNITED STATES PATENTS Number Name Date 1,773,294 Benner Aug. 19, 19301,922,872 Thompson Aug. 15, 1933 2,298,641 Schulze et al s Oct. 13, 19422,384,926 Jones Sept. 18, 1945 2,388,259 Fleming et al. Nov. 6, 19452,497,095 Nevins et a1. Feb. 14, 1950 2,561,990 Miller July 24, 1951FOREIGN PATENTS Number Country Date 120,554 Great Britain Sept. 25, 1918(Complete not accepted; application date cited) 267,138 Great BritainDec. 15, 1927

1. IN THE RECOVERY OF ELEMENTAL SULPHUR IN LIQUID FORM FROM GASESCONTAINING H2S INVOLVING THE CONTACT OF A CATALYST WITH THE GASCONTAINING H2S TO FORM SULPHUR VAPOR AND THE SUBSEQUENT TREATMENT OF THECATALYST IN AN OXIDIZING ATMOSPHERE TO REGENERATE THE CATALYST FORFURTHER CONTACT WITH THE GASES CONTAINING H2S AND THE SUBSEQUENTCONDENSATION OF THE SULPHUR VAPOR TO FORM LIQUID SULPHUR, THEIMPROVEMENT WHICH COMPRISES ROTATING A SERIES OF SEPARATED THIN BEDS OFCATALYST DIRECTLY AND IN SUCCESSION AND SUBSTANTIALLY CONTINUOUSLYRELATIVE TO AND THROUGH A SERIES OF REACTION ZONES AND A REGENERATINGZONE; CONTINUOUSLY DIRECTING THE FLOW OF THE GAS TO BE TREATED INSUCCESSION AND IN SERIES THROUGH SAID REACTION ZONES; SUBJECTING THE GASTO BE TREATED TO HEAT EXCHANGE TO BRING ITS TEMPERATURE TO AN OPTIMUMREACTION TEMPERATURE AND MIXING A PREDETERMINED AMOUNT OF OXIDANT WITHIT PRIOR TO ITS PASSAGE THROUGH EACH OF THE REACTION ZONES TO CONVERT APORTION OF THE H2S IN EACH OF SAID ZONES INTO SULPHUR VAPOR AND STEAM;CONTINUOUSLY WITHDRAWING THE TREATED GAS FROM THE LAST ONE OF THEREACTION ZONES AND DIRECTING ITS FLOW THROUGH A CONDENSING ZONE ANDTHERE CONDENSING THE SULPHUR VAPOR TO FORM LIQUID SULPHUR; ANDCONTINUOUSLY DIRECTING THE FLOW OF A HOT OXIDIZING MEDIUM THROUGH THEREGENERATING ZONE TO REACTIVATE THE CATALYST THEREIN.